This invention relates generally to display technology and more particularly to the design and fabrication of three-dimensional television displays and three-dimensional computer displays.
Integral photography has proven to be able to reproduce high-resolution three-dimensional images, which exist independently of the observer. This is in contrast to stereoscopic type images where the spatial content only exists in the mind of the observer.
Integral photography stores information in the focal (or equivalent) plane of each microlens containing the amount of light that has to be emitted by this microlens in each separate direction. With such systems, there is indeed a complete image behind each microlens. This technique is adequate for three-dimensional photography, but this technique is not suitable for use in three-dimensional television, due to the high information density that is required to be transmitted.
The bandwidth required to transmit sufficient integral photography data in order to obtain an image with traditional television resolution has been calculated to be on the order of 40.5 GHz (see Burckhardt, xe2x80x9cOptimum Parameters and Resolution Limitation of Integral Photographyxe2x80x9d, Journal of the Optical Society of America, Volume 58 (1), 1968, pp 71-76). This bandwidth increases further to the fourth power of the desired screen resolution
What is needed in the art, therefore, is a method for generating and reconstructing a three dimensional, high resolution image that can be transmitted using conventional broadcast signals that does not require excessive bandwidth for transmission.
Preferred embodiments of the present invention provide a solution to the disadvantages of the prior art systems and methods. Preferred embodiments of the invention involve a technique that reconstructs the complete information density in the focal plane of each microlens of the microlens array, The system uses normal two-dimensional display information to which has been added depth information for each pixel. The final information density (bandwidth) needed to reconstruct the three-dimensional image using this technique is not substantially higher than the information density needed to reconstruct a two-dimensional image. The described system is constructed such that the signal used for three-dimensional television can be used on a two-dimensional television and that the signal used for two-dimensional television can be used on a three-dimensional television, what is called forward and backward compatibility. This technique allows, as such, a continuous evolution in consumer television from two-dimensional television to three-dimensional television.
In one aspect, the present invention provides a display device for generating a three-dimensional image from an image signal, the image signal including depth information. The display device comprises an array of microlenses having a first pitch in a first direction and an array of light sources impinging upon the microlens array and having a second pitch in the first direction, the second pitch being variable. The second pitch of the array of light sources varies in response to the depth information of the image signal.
In another aspect, the invention provides for a device comprising a display plate having an array of microlenses thereon, each microlens of the array having a central axis, wherein each microlens of the microlens array has a plurality of illumination locations relative to the central axis of the microlens. Further included is a selection circuit receiving as input depth information corresponding to a given microlens and outputting a selection signal corresponding a desired illumination location for the given microlens and an illumination circuit receiving as input the selection signal and causing in response illumination of the desired illumination location.